Between 1980 and 1984 Gaddafi had ordered the deaths of several exiled opponents of his regime; bombings and shootings, targeted at Libyan dissidents, occurred in Manchester and London. Five Libyans thought to be behind the attacks were deported from the UK. During the anti-Gaddafi protest on 17 April 1984, two gunmen opened fire from the first floor of the embassy with Sterling submachine guns. In addition to the murder of Fletcher, eleven Libyan demonstrators were wounded. The inquest into Fletcher's death reached a verdict that she was "killed by a bullet coming from one of two windows on the west side of the front on the first floor of the Libyan People's Bureau". Following the breaking of diplomatic relations, Libya arrested six British nationals, the last four of whom were released after nine months in captivity.
Two years after Fletcher's murder, the event became a factor in the decision by the British prime minister, Margaret Thatcher, to allow the US bombing of Libya from bases in the UK. In 1999 a warming of diplomatic relations between Britain and Libya led to a statement from the Libyan government admitting culpability in Fletcher's shooting, and the payment of compensation. British police continued their investigation until 2017. Although sufficient evidence existed to prosecute one of the co-conspirators, no charges were brought as some of the evidence could not be raised in court due to national security concerns. As at 2018 no one has been convicted of Fletcher's murder.
Yvonne Joyce Fletcher was born on 15 June 1958 in the Wiltshire village of Semley, to Michael Fletcher and his wife Queenie (née Troke). Yvonne was the eldest of the couple's four daughters. At the age of three she told her parents that she wanted to join the police. By the time she was eighteen and a half—the minimum entry age into the Metropolitan Police Service—she was 5 feet 2.5 inches (1.59 m) tall, shorter than the 5 feet 4 inches (1.63 m) required. She applied to several police forces but was turned down on the basis of her height, and considered applying for entry to the Royal Hong Kong Police Force.
Despite the height restriction, in March 1977 Fletcher was accepted onto the Metropolitan Police 20-week training course. She passed and was placed on the standard two-year probation period with the warrant number 4257; she was posted to Bow Street police station, where she completed her probation and was confirmed as a regular Woman Police Constable (WPC). She was highly regarded by her colleagues, who nicknamed her "Super Fletch", and she became engaged to PC Michael Liddle, who also worked at Bow Street.
From 1979 there had been no Libyan ambassador appointed to the United Kingdom. A "Revolutionary Committee" was in control of the Libyan embassy in London, located at 5 St James's Square; the embassy was renamed the "People's Bureau". In 1980 Libya's leader, Muammar Gaddafi—the Chairman of the Revolutionary Command Council—saw many exiles from Libya as traitors and had given orders for several of them to be murdered. On his instructions, bombs were planted in London newsagents that sold newspapers critical of Gaddafi. Moussa Koussa was appointed as Secretary of the Libyan People's Bureau in London in 1979. He was expelled from the UK in 1980, after stating in an interview with The Times that the Libyan government planned to murder two opponents of Gaddafi's government living in the UK. The Lord Privy Seal, Sir Ian Gilmour, told the House of Commons that the government wished "to maintain good relations with Libya", but that "we are making it clear that the Libyan authorities must understand what can and cannot be done under the law of the United Kingdom, and that criminal actions in the United Kingdom must cease".
After several murders of Gaddafi's political opponents in the UK in 1980, there was a decrease in activity until 1983, when the Libyan General People's Congress—the country's legislature—began a campaign against what they saw as the bourgeois habits of staff at several of the People's Bureaux, particularly the office in London. In February 1983 the bureau chief and cultural attaché were recalled to Libya and replaced with a four-man committee of students who had all been involved in revolutionary activities in Libya. Soon after they were appointed, they gave a press conference at which they threatened action against Libyan dissidents. On 10 and 11 March 1984 there were a series of bomb attacks in London and Manchester targeted at critics of the Gaddafi regime. The Libyan government denied being involved, but on 16 March the British government deported five Libyans said to be connected to the attacks.
The protection of diplomats and their official premises is based on the Vienna Convention on Diplomatic Relations 1961, an international treaty; it was signed by 141 countries, including the UK and Libya. It was incorporated into UK law in the Diplomatic Privileges Act 1964. Among other measures, the act protects diplomats from prosecution for any crime unless the diplomat's home country waives his right to immunity. A country can declare a diplomat from another state to be persona non grata, and demand that they leave the country, but no other action can be taken against them. Diplomatic premises are also protected from entry by the police or security services, unless given permission by the country's ambassador.